System of automatic block-signaling for electric railways.



P. TOWNSEND. SYSTEM ()1? AUTOMATIC BLOCK SIGNALING FOR ELECTRICBAILWAYS.

APPLICATION FILED APR.27, 1905 WITNESSES 15 NORRIS PETERS (30..FHOYQLITHQ. WASHINGTON. D. C,

F. TOWNSEND. SYSTEM OF AUTOMATIC BLOCK SIGNALING FOR ELECTRIC RAILWAYS.

APPLICATION FILED APR.27, 1905.

BET 2.

Patented Feb. 23, 1915.

LIQQUL -IE.

WITNESSES:

ATTORNEY F. TOWNSEND. SYSTEM OF AUTOMATIC BLOCK SIGNALING FOR ELECTRICRAILWAYS.

APPLICATION FILED APR. 27, 1905.

1,19,143, Patented Feb. 23, 1915.

F 3 SHE] TS-SHEET 3.

1i\ my a? N \-1- N f S N D f ATTORNEY THE NORRIS PETERS C0 PHOTCVLITHCL.WASHINGTON. r

FITZHUG-H TOWNSEND, OF NEW YORK, N. Y., ASSIGNOR TO GENERAL RAILWAYSIGNAL COMPANY, A CORPORATION OF NEW YORK. I

SYSTEM OF AUTOMATIC BLOCK-SIGNALING FOR ELECTRIC RAILVVAYS.

ineaiia.

Specification of Letters Patent.

Patented Feb. 23, 1915.

Original application filed .Tune 16, 1904, Serial No. 212,798. Dividedand this application filed Apri1 27,

' a citizen of the United States, residing at New York city, county ofNew York, State of New York, have invented a System of AutomaticBlock-Signaling for Electric Railways, of which the following is aspecification.

My invention relates to a system where the operation of the signals iscontrolled by the motion of a motor vehicle into and out of a block andwhile in the block. In the practical operations of such a system,

several requirements must be fulfilled in order that the normalconditions of operation of the railway shall not be interfered with, i.6., the traflic rails must be segregated into block sections, the powercurrent which operates the motor vehicle must flow along the trailicrails from one block section to the neXt without being impeded, thetraffic rails should have an equal conductivity and both serve as returnconductors for the power current, and means provided to increase theconductivity of the return circuit when desired, by what is technicallyknown as f returnv'or negative feeders.

Systems of automatic block signaling have heretofore been proposedwhich, in a measure, complied with one or more of the above statedrequirements. In one of such systems, the traffic rails have beendivided into block sections by means of insulating joints, and in orderto facilitate the return of the power current, such joints have beenbridged by reactance coils. Such system, however, does not give acomplete use of the divided rail as a conductor for the power current.Where such system is supplied by a direct power current, the reactancecoils interposed between the ends of the sections of the divided railmaterially increase the ohmic resistance of the divided rail relative tothat of the continuous rail, with the result, that the major portion ofthe power current is diverted to the continuous rail. Consequently,instead of having two rails of equal resistance, as a return for thepower current as in ordinary railways, the conductivity of the tworails, divided and continuou's,is equal only to approxi- Serial No.257,572.

mately that of one rail and a fraction. WVhere such a system is suppliedby an alternating power current, the disadvantage mentioned is found tobe greatly increased, by the fact that the reaotance coils oppose acounter-electro-motive force of self-induction, as well as ohmicresistance to the power current, with the result that the currentcarried by the divided rail is still further diminished relative to thatcarried by the continuous rail.

In the system which I have designed, both traffic rails are divided intoblock sections by insulation interposed between the ends of the rails.In order to allow the power current to return along the trafiic railsand pass from one block section to the next, I interpose what I termbonding-coils between the rails at the points of division between theblocks and in such manner that the power current flows through eachbonding coil (in at both ends and out at the middle point of the coil)in such manner as to produce no magnetization of the core on which thecoil is wound. The advantage secured by the arrangement of thebondingcoils as employed by me, are: Owing to the small amount of ironand copper required to form the bond, such bonds are cheap inconstruction. The drop in volts due to the passage of the power currentthrough the bonding-coils is greatly diminished. In the case of analternating current railway, (where the power current produces nomagnetization in the bonding-coils at any time), nocounter-electro-motive force of self-induction will impede the powercurrent in its passage along the traffic rails from one block section tothe next.

My improved system is applicable to roads operated either by direct oralternating current.

In order to control the signaling devices, an alternating current isemployed, (irrespective of whether the power current is a direct or analternating current), which is preferably fed into each block section atthe end of the block at which the car normally leaves the block; (thiscurrent I shall denote in this specification as the signaling .current)The signaling current produces a difference of potential between thetraffic rails, which difference of potential is adapted to normally,that is, when a block is not occupied by a motor vehicle, energize arelay device connected across the traflic rails, preferably at the endof the block section at which the car normally enters the block. Thisrelay device normally acts to close a local circuit in such a way thatthe signaling device employed will indicate a clear signal. The presenceof a motor vehicle in a block section, through the wheels and axles ofthe car, or any suitable contact device, serves to short circuit therelay device; or in other words, shunt the difference of potentialaround the relay device, thus denergizing the relay and causing thesignaling device to indicate a danger signal. The relay employed may beof any definite type. I prefer, however, to use a relay which will beselective in character, and such as will only be actuated by anelectromotive force across the rails, having the particular frequency ofthe signaling current employed. I have described in this specification aparticular form of relay. I, however, make no claim in this applicationfor such rela The signaling current employed may be derived from anysuitable source. In the drawings I have shown three different methods ofobtaining signaling current; that is, the signaling current may beobtained from an independent generator, Figures 1 and 4, from thegenerator which furnishes the power current, (the power current being ofone phase and the signaling current of another phase), Fig. 2, and fromthe same generator which furnishes the power current but as a segregatedcurrent, Fig. 8.

The accompanying drawings will serve to illustrate my invention, .inwhich- Fig. l is a diagram illustrating my improved system as applied toan alternating current railway, with two generators, one for the powercurrent, and one for the signaling current. Fig. 2 shows my system asapplied to an alternating current railway, with a single generatoremploying one phase for the power current and one phase for thesignaling current. Fig. 3 shows my system as applied to an alternatingcurrent railway with a single generator, with the signaling currentsegregated from the power current. Fig. 4 shows my system as ap plied toa direct current railway, with a direct current generator for the powercurrent and an alternating generator for the signaling current.

Referring to the drawings: A indicates the generator for the powercurrent. In Figs. 1 and 3, this generator is an alternating currentgenerator of the single phase type, in Fig. 2, an alternative currentgenerator of the two phase type, and in Fig. 4

a direct current generator. I wish it understood that the power currentmay be derived from any suitable source of electricity, as is the casewith ordinary electric railways, that is, the power current may be analternating current of single phase or polyphase, a direct current, or apulsating current.

B, Figs. 1 and 4, indicates the generator for the signaling current. InFigs. 2 and 3, the signaling current is derived from the generator A,which furnishes the power cur rent. In Fig. 2, the signaling current istaken off from a different set of collector rings of the generator Afrom that of the power current and differs in phase from the powercurrent, and which current is used to excite the primary 5 of atransformer C. In Fig. 3, the signaling current is a segregated currentfrom the power current delivered from generator A, as will be described.

6 indicates the outgoing feeder contact conductor; D motor vehicle; 7,traveling contact; 8, 9, traffic rails. The traffic rails are showndivided into three blocks or sections X, Y, Z; the corresponding railsof respective sections being insulated from each other or otherwiseseparated. The feeder contact conductor (3 and the rails S, 9 areconnected to the terminals of the power generator A and form a powercircuit.

In order to connect the traffic rails S, 9 of the blocks X, Y, Z,together, and thus furnish two return paths for the power current to thegenerator A, and which paths shall be of equal resistance, I make use ofthe bond E, which consists of an iron core 10, on which is wound a coilof copper wire 11, which coil is connected across the rails 8, 9, at theleft hand end of each block. Also the bond transformer F, which consistsof the core 12, on which is wound the copper wire coils 13, 14. The coil13 is connected, like the coil 11, across the trafiic rails 8, 9, but atthe opposite end of each block. The coil 14 is connected, one end to thecenter of the coil 13, and the other end to a conductor 15. A feederconductor 15 is connected at one end to the source of the signalingcurrent, that is, in Figs. 1 and 4, to one termi nal of the generator B;in Fig. 2, to one terminal of the secondary 16 of transformer C; in Fig.3 a feeder contact conductor 6 takes the place of the conductor 15. Thecoil 14 forms the primary coil of the bond transformer F, and as it isconnected across the terminals of the signaling current, serves toexcite the coil 13, which coil serves a double purpose, i. 0., that of abond and that of the secondary of transformer F. The current from eachcoil delivered to the traffic rails S, 9, creates a difference ofpotential between these traiiie rails, which current is used, as willhereafter be described, to operate a relay when a motor car is not in ablock, but

mamas which current is short-0ircuited when a motor car moves into ablock. The coils 11, 13 of bond E and bond transformer F, are connectedtogether at their middle point, by means of a conductor 17.

The operation of the bond E and bond transformer F, so far as relates totheir function as a bond, will now be understood. The power current froma rail 8 flows through the left hand half of the coil 11 to conductor17, while the current from rail 9 flows through the right hand half ofthe coil 11 to conductor 17. As the direction of the flow of these twocurrents is opposite, no magnetization of the core 10of bond E will takeplace. The currents which have joined in the conductor 17 are deliveredto the center of the coil 13 on bond transformer F, divide and flowthrough opposite halves of the coil 13, respectively to the rails 8 and9 of the next section, for instance X, and as they flow in oppositedirections do not magnetize the core 12. The coils 11, 13, therefore donot offer any considerable resistance to the power current (whether itbe a direct or alternating current) flowing to the generator through thetraflic rails 8 and 9. It

will be observed, however, that the coils 11 and 13 are connected acrossthe rails 8, 9; consequently, the current due to the difference ofpotential excited between the rails 8, 9, by the coil 13 acting assecondary of the bond transformer F and tending to flow through thewhole of coil 11 of bond E in one direction, is met by the reactanceeffect of the whole of coil 11, which practically resists the flow ofsuch current and thereby tends to maintain the potential of thesignaling current across the rails 8, 9.

The conductor 17, it will be observed, at the left hand end of the blockX, is connected in Figs. 1 and 4-, to the generators A, B, in Fig. 2, tothe generator A and one terminal of the coil 16 of the transformer C, inFig. 3, to the generator A. The conductor 17, it will be observed, alsoforms a common return for both the power and the signaling currentemployed in all of the figures.

Instead of using a bond E and transformer F, as shown in Figs. 1, 2, 3,I may use two bonds of similar construction, as shown in Fig. 4c, andexcite the difference of potential across the rails 8, 9, by means of anindependent transformer Gr, having its primary 18 connected across theconductors 15 and 17, and its secondary 19 across the traffic rails 8and 9.

Referring now to the relay device, the relay device may have its fieldcoil 20, connected directly across the source of signaling current, .asshown in Figs. 2, 3 and 4, or across the terminals of the secondary coil21 of a transformer I, as shown in Fig. 1, the primary 22 of which isconnected across the conductor 15 and a conductor 23; one terminal ofthe primary is also connected to the conductor 17. Located in the fieldcoil 20 of the relay H, is a device J, Fig. 1, through which aninductive resistance may be interposed in the field circuit of therelay.

K indicates the armature of the relay, which consists of a coil of wire26%, whose plane in its normal condition is parallel with the field offorce between the pole pieces of the relay. The terminals of this coilare connected across the rails 8, 9. Carried by this armature is an arm25.

26 indicates a local circuit, in which is a solenoid core 27. One end ofthe local circuit is fastened to the arm 25 and the other end to acontact plate 28.

29 indicates an armature located in the solenoid 27, and connected tothe short arm of the semaphore 30.

In certain localities, as for instance, upon elevated roads, it isuseful to decrease the resistance of the return path for the powercurrent, and for this purpose I provide the additional connecting feederbonds L, which are constructed in all respects like the bonds E and eachof which has its coil 31 connected across the rails 8, 9, and also atits central point through a conductor 32 to the conductor 23, whichconductor may, for instance, be the structure of an elevated road, orother good conducting path.

' The operation of my improved system is as follows z-The signalingcurrent derived from the generator B, or from one phase of the generatorA, but segregated from the power current, Fig. 3, excites through thetransformer bonds F, Figs. 1, 2, 3, or supplemental transformer G, Fig.4:, a diflerence of potential between the rail 8, 9. It will be seenthat the power curreint, which may be direct or alternating, flows alongthe traffic rails at the same time as the signaling current, there beingno interference between the two currents. The signaling current alsoexcites the field coil 20, of the relay H, either directly as shown inFigs. 2, 3, 1, or through the instrumentality of a transformer I, asshown in Fig. 1. The voltage across the rails 8, 9, excites a current inthe coil 24. Remembering now that the signaling current exciting thefield coil 20 of the relay I-I corresponds in phase with the currentexciting the coil 24:, of the armature K, a turning movement of thearmature K will take place, which turning movement will cause the arm 25to make contact with the plate 28 and close the local circuit 26,thereby causing the solenoid 27 to attract its armature 29 and carry thesignal to the clear position, i. e., the position shown in blocks X andZ. The semaphore arm will be maintained in this position so long as avoltage exists across the rails 8, 9. Should this Voltage be destroyedby any means, as for instance, by malicious inter- &

ference or otherwise, the semaphore arm will automatically go to danger.Or, in the normal operation of the road, a car entering a block, inwhich case the wheels of the car and axles will short circuit thearmature K of the relay. Or, in other words, prevent the current due tothe difference of? potential between the rails 8, 9 from flowing throughsaid armature, with the result that the armature will return to itsnormal position and open the local circuit, thereby allowing thesemaphore arm to drop by gravity to the danger position.

In the various diagrams I have shown the rails included in the primarycircuit of the transformers. ldanifestly, and to insure greater safety,I may excite the transformers which create a difference of potentialacross the rails by means of entirely independent conductors.

I wish it understood that I do not limit myself to the particulararrangement of circuits indicated in the accompanying diagrams, as itWill be obvious to electricians, that many changes may be made withoutin any wise departing from the intent of my invention. Nor do I limitmyself to the particular construction of bond or bond transformer, orrelay, shown, as many changes may be made therein without involving anyradical change in the operation of the system.

What I wish to have understood is-that I claim to be the first to havedescribed and illustrated a system of automatic block signaling forelectric railways where the conductivity of the traffic rails ispractically the same, and will be maintained the same as in an ordinaryelectric railway, and which conductivity is not effected by havingimpressed thereon in the direction of the flow of the both rails dividedinto block sections, signaling devices for each block, an alternatingcurrent generator for supplying alternating currents for said signalingdevices and also supplying the power currents for the operation ofelectric cars of the railway independent of the signaling devicescontrolled thereby, coils bridging the rails of each section at each endthereof and a conductor between the middle points of adjacent coilsthrough which the power currents pass unimpeded by reactance, andtransformers receiving currents from said generator and supplying saidsignaling devices.

In a system of automatic block signaling for electric railways, thecombination with the usual contact conductor or third rail, of analternating current generator adapted to generate a plurality of phasesand having one terminal of one phase connected to the contact conductoror third rail,

- a coil joining the ends of the tra'fIic rails, the

other terminal of said phase being connected to the central point ofsaid coil, signaling devices tor each block, and a transformer connectedto another phase of said alternator and its secondary supplying currentto the s1 gnahng devices.

In testimony whereof, I afiix my signature, m the presence or twowitnesses.

FITZHUG-H TONNSEND lVitnesses V. H. PUMPHREY, M. G. CRAWFORD.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents.

Washington, D. 0."

lie

